Log Message:
Update to 1.17. Changes:

        * Added new option '-l, --logfile-size'.
        * Added new option '-w, --ignore-write-errors'.
        * Option '--fill' has been renamed to '--fill-mode'.
        * Option '--generate-logfile' has been renamed to '--generate-mode'.
        * Added option '--sector-size' as a synonym of '--block-size'.
        * Added option '--retries' as a synonym of '--max-retries'.
        * Added option '--size' as a synonym of '--max-size'.
        * rescuebook.cc: Trimming is now done from both edges of each
          non-trimmed block. Largest blocks are trimmed first.
        * rescuebook.cc: Largest blocks are now split first until
          logfile reaches '--logfile-size' entries.
        * logbook.cc (extend_sblock_vector, truncate_vector): Terminate
          if truncation would discard finished blocks.
        * rescuebook.cc: Mark failed blocks with 1 sector as bad-sector.
        * logbook.cc (extend_sblock_vector): Remove last block of
          logfile if it starts at isize and is not marked as finished.
        * Documented that 'direct disc access' only reads whole sectors.